Recent news of an impending clinical cell transplantation trial in Parkinson's disease using parthenogenetic stem cells as a source of donor tissue have raised hopes in the patient community and sparked discussion in the research community. Based on discussions held by a global collaborative initiative on translation of stem cell therapy in Parkinson's disease, we have identified a set of key q...

Background: Artificial oocyte activation (AOA) has important implications in assisted reproductive technique (ART) with particular importance in somatic cell nuclear transfer (SCNT). Parthenogenesis activation using zona- free oocytes offers an alternative model that could be applied to develop protocols for the activation of reconstructed embryos for cloning. Materials and Methods: To establis...

In the well studied model nematode Caenorhabditis elegans entrance of the sperm induces an anterior-posterior polarity in the egg and determines the orientation of the primary embryonic axis. Subsequently, fusion of two haploid gamete nuclei results in a diploid zygote as a prerequisite for normal embryogenesis. Here we analyze the establishment of embryonic polarity and diploidy in the absence...

This study describes the initial phases of wing morphogenesis of Megoura viciae Buckton (Homoptera Aphididae). We evaluated the development of wing buds in males (winged) and parthenogenetic females (presumed to become wingless) of M. viciae from birth to 4 instar. Wing bud epithelium in males is initially simple, becoming bistratified and then progressing to stratify. Mitotic activity is more ...

Background: The advances in cytogenetic techniques during the last few years have permitted not only the study of large populations of wild and domestic animals, but also the detection of chromosome anomalies in embryos. Chromosomal abnormalities are the most common cause of embryonic and fetal mortality in mammals. Most reports of chromosome anomalies in parthenogenetic embryos describe numeri...

Parthenogenetic activation of Lytechinuspictus eggs can be monitored after inje&ion with the Ca-sensitive photoprotein aequorin to estimate calcium release during activation. Parthenogenetic treatments, including the nonelectrolyte urea, hypertonic sea water, and ionophore A23187, all acted to release Ca2+ from intracellular stores. Ionophore and urea solutions release Ca*’ from the same intrac...

Transitions to asexuality have occurred in many animals and plants, yet the biological mechanisms causing such transitions have often remained unclear. Cyclical parthenogens, such as cladocerans, rotifers or aphids often give rise to obligate asexual lineages. In many rotifers, chemical signals that accumulate during population crowding trigger the induction of sexual stages. In this study, I t...

The Leptynia hispanica stick insect species complex includes bisexuals, triploid and tetraploid parthenogenetic populations, suggesting that polyploidy has played a central role in the evolution of this complex. An analysis of karyotype, mitochondrial DNA (cox2) and nuclear DNA (ef1-alpha) markers was carried out to clarify phylogenetic relationships and microevolutionary/phylogeographical patt...